Prince Frank is the young prince of neighboring Goldland and Sapphire's love interest. Their relationship is complicated; Frank is familiar with Sapphire as three entirely different people, and has different feelings toward each. He is good friends with Prince Sapphire, in love with the unnamed princess, and despises the Phantom Knight, whom he believes is a rival for the Princess's affection. Because of their similar upbringings, Frank has many of the same skills as Sapphire, although Sapphire is usually a bit better. Tezuka, who was unsatisfied with the original manga series, added some improvements in story and characters to the TV series. He cast the recurrent character Rock as Prince Frank while adding more depth and improving his abilities.